1. Field of the Invention
The invention relates to a retraction ball for a hydrostatic piston machine and a system comprising a retraction ball for a hydrostatic piston machine and at least one elastic element, wherein the retraction ball provides a recess for the accommodation of the elastic element, in which a structural element is formed for the locking of the elastic element.
2. Description of the Background Art
An axial piston machine with a housing, in the interior space of which a cylindrical drum is mounted, is known from DE 100 35 630 C1, which corresponds to U.S. Pat. No. 6,880,450. The cylindrical drum is mounted about a coaxial drive shaft and connected to the latter in a rotationally rigid manner. Axially extending piston boreholes, in which pistons are guided in a displaceable manner, are formed within the cylindrical drum. The pistons are supported via guide shoes against a rotating disk. The rotating disk is mounted in a rotatable manner about a rotational axis extending perpendicular to the axis of the drive shaft and forms a diagonal running surface, over which the guide shoes can slide. During the functional operation of the axial piston machine, the drive shaft and the cylindrical drum rotate about a common axis. The pistons are displaced in a reciprocating manner within the piston boreholes. A lifting of the guide shoes from the running surface during the suction stroke is prevented by a retraction device. The retraction device holds the guide shoe in contact with the running surface. The retraction device is formed by a retraction disk, which engages behind the flange of the guide shoe. The retraction disk is supported axially with a spherical-zone-shaped, concave bearing surface against a correspondingly spherical-zone-shaped, convex bearing surface of a so-called retraction ball. The retraction ball is preferably connected in a rotationally rigid manner to the drive shaft by a multi-toothed coupling and is mounted on the drive shaft in an axially displaceable manner and supported in the direction towards the cylindrical drum.
The use of springs to support the retraction ball in the direction towards the cylindrical drum is known. Accordingly, the support is elastic, and the position of the retraction ball is adapted to the changing conditions during operation, for example, through the influence of temperature. Recesses are formed in the retraction ball to accommodate the springs in the retraction ball.
The disadvantage with the previous recesses or respectively with the previous system having a retraction ball and incorporated springs is that the springs can fall out during the fitting or removal of the system into or from the axial piston machine. This makes the fitting or removal awkward. Attaching the springs in the recesses of the retraction ball for a simplified fitting of the retraction ball using grease or high-viscosity material is known. This method has the disadvantage that the grease or the high-viscosity material is drained from the recesses in the axial piston machine because of high operating temperatures and because of leakage flows, and the springs can fall out again during the removal of the retraction ball. Fixing the springs in the recesses of the retraction ball is not permanent and only simplifies the fitting, but not the removal of the system comprising the retraction ball and the incorporated springs.